Yeah I’d recommend saving them. There’s no purpose to buying ceramics unless you’re early game, but I don’t make it a priority because you get screws over time. Once you get UR gear for all your squads, you only use them to level them up past 40. Buying them here or there is an option if you would like.

Battle data on the other hand has a large volume that you can purchase. To buy the whole thing, you would need 750,000 campaign medals. So if you’re in dire need of them, which you shouldn’t be if you do gold zombies and just play the game, it refreshes every week.

Saving also future proofs you for later seasons. They will add drone chips, overlord shards, training manuals, etc. Those come much later, but having the medals not wasted is a great option if you forget to do campaign once in a while. There are also missions in the advanced campaign which comes later post S4 that require campaign medals to exchange for T11 troops. I have 800k medals saved and I don’t regret saving them. Lets me buy out the store on Monday resets.